extern int printf(const char* __restrict__format, ...);

int main(){
    #ifdef __x86_64__
        printf("x86_64\n");
    #else 
        printf("x86\n");
    #endif
    //这种macro可以用来做一些跨平台的适配

    #if aa == bb
        printf("yes\n");
    #else
        printf("no\n");
    #endif
}